5 1990: The results below are measurements of cumulative oxygen consumption by germinating and dry seeds. Gas volume measurements were corrected for changes in temperature and pressure.
6 Cumulative Oxygen Consumed (mL) ______________________________________________ Time (minutes) ______________________________________________ o C Germinating Seeds Dry Seeds ______________________________________________ o C Germinating Seeds Dry Seeds ______________________________________________
7 Using the graph paper provided, plot the results for the germinating seeds at 22o C and 0o C. b. Calculate the rate of oxygen consumption for the germinating seeds at 22o C, using the time interval between 10 and 20 minutes. c. Account for the differences in oxygen consumption observed between: 1) germinating seeds at 22o C and at 10o C; 2) germinating seeds and dry seeds. d. Describe the essential features of an experimental apparatus that could be used to measure oxygen consumption by a small organism. Explain why each of these features is necessary.
8 1989: Explain what occurs during the Krebs (citric acid) cycle and electron transport by describing the following: a. The location of the Krebs cycle and electron transport chain in the mitochondria. b. The cyclic nature of the reactions in the Krebs cycle. c. The production of ATP and reduced coenzymes during the cycle. d. The chemiosmotic production of ATP during electron transport.
16 The diagram below shows a segment of DNA with a total length of 4,900 base pairs. The arrows indicate reaction sites for two restriction enzymes (enzyme X and enzyme Y).
17 Explain how the principles of gel electrophoresis allow for the separation of DNA fragments. Describe the results you would expect from the electrophoresis separation of fragments from the following treatments of the DNA segment above. Assume that the digestions occurred under appropriate conditions and went to completion. DNA digested with only enzyme X DNA digested with only enzyme Y DNA digested with enzyme X and enzyme Y combined Undigested DNA Explain both of the following. The mechanism of action of restriction enzymes. The different results you would expect if a mutation occurred at the recognition site for enzyme Y.
18 Another ex. Describe the biochemical composition, structure, and replication of DNA. Discuss how recombinant DNA techniques may be used to correct a point mutation.
19 Describe the steps of protein synthesis, beginning with the attachment of a messenger RNA molecule to the small subunit of a ribosome and ending generalized with the release of the polypeptide from the ribosome. Include in your answer a discussion of how the different types of RNA function in this process.
20 A portion of specific DNA molecule consists of the following sequence of nucleotide triplets. TAC GAA CTT GGG TCC This DNA sequence codes for the following short polypeptide. methionine - leucine - glutamic acid - proline - arginine Describe the steps in the synthesis of this polypeptide. What would be the effect of a deletion or an addition in one of the DNA nucleotides? What would be the effects of a substitution in one of the nucleotides?
23 By using the techniques of genetic engineering, scientists are able to modify genetic materials so that a particular gene of interest from one cell can be incorporated into a different cell.
24 Describe a procedure by which this can be done Describe a procedure by which this can be done. Explain the purpose of each step of your procedure. Describe how you could determine whether the gene was successfully incorporated. Describe an example of how gene transfer and incorporation have been used in biomedical or commercial applications.
25 Experiments by the following scientists provided critical information concerning DNA. Describe each classical experiment and indicate how it provided evidence for the chemical nature of the gene. Hershey and Chase- bacteriophage replication Griffith and Avery, MacLeod and McCarty- bacterial transformation Meselson and Stahl- DNA replication in bacteria
26 An organism is heterozygous at two genetic loci on different chromosomes. Explain how these alleles are transmitted by the process of mitosis to daughter cells. Explain how these alleles are distributed by the process of meiosis to gametes. Explain how the behavior of these two pairs of homologous chromosomes during meiosis provides the physical basis for Mendel’s two laws of inheritance.
45 In fruit flies (Drosophila melanogaster), the phenotype for eye color is determined by a certain locus. E indicates the dominant allele and e indicates the recessive allele. The cross between a male wild-type fruit fly and a female white-eyed fruit fly produced the following offspring:
55 Do the following with reference to the Hardy-Weinberg model Do the following with reference to the Hardy-Weinberg model. Indicate the conditions under which allelic frequencies (p and q) remain constant from one generation to the next. Calculate, showing all work, the frequencies of the alleles and the frequencies of the genotypes in a population of 100,000 rabbits, of which 25,000 are white and 75,000 are agouti. (In rabbits the white color is due to a recessive allele, w, and the agouti is due to a dominant all, W.) If the homozygous dominant condition were to become lethal, what would happen to the allelic and genotypic frequencies in the rabbit population after two generations?
56 In a laboratory population of diploid, sexually reproducing organisms a certain trait is studied. This trait is determined by a single autosomal gene and is expressed as two phenotypes. A new population was created by crossing 51 pure breeding (homozygous) dominant individuals with 49 pure breeding (homozygous) recessive individuals. After four generations, the following results were obtained.
58 Identify an organism that might have been used to perform this experiment, and explain why this organism is a good choice for conducting this experiment. On the basis of the data, propose a hypothesis that explains the change in phenotypic frequency between generation 1 and generation 3. Is there evidence indicating whether or not this population is in Hardy-Weinberg equilibrium? Explain.
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